/*
 * Copyright 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.clientmiviamoviego4;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageButton;

/**
 * Un ImageButton che viene esteso per supportare comportamenti custom.
 * 
 * @author Gang of Four
 */
public class TouchHighlightImageButton extends ImageButton {
	/**
	 * Riferimento al drawable evidenziato.
	 */
	private Drawable mForegroundDrawable;

	/**
	 * Variabile relativa ai contorni nascosti della view.
	 */
	private Rect mCachedBounds = new Rect();

	/**
	 * Costruttore della classe TouchHighlightImageButton
	 * */
	public TouchHighlightImageButton(Context context) {
		super(context);
		init();
	}

	/**
	 * Costruttore della classe TouchHighlightImageButton
	 * */
	public TouchHighlightImageButton(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	/**
	 * Costruttore della classe TouchHighlightImageButton
	 * */
	public TouchHighlightImageButton(Context context, AttributeSet attrs,
			int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	/**
	 * Inizializzazione della view.
	 */
	private void init() {
		// Reset default ImageButton background and padding.
		setBackgroundColor(0);
		setPadding(0, 0, 0, 0);

		// Retrieve the drawable resource assigned to the
		// android.R.attr.selectableItemBackground
		// theme attribute from the current theme.
		TypedArray a = getContext().obtainStyledAttributes(
				new int[] { android.R.attr.selectableItemBackground });
		mForegroundDrawable = a.getDrawable(0);
		mForegroundDrawable.setCallback(this);
		a.recycle();
	}

	/**
	 * Metodo chiamato quando lo stato del drawable cambia. Viene forzata una
	 * redraw.
	 * */
	@Override
	protected void drawableStateChanged() {
		super.drawableStateChanged();

		// Update the state of the highlight drawable to match
		// the state of the button.
		if (mForegroundDrawable.isStateful()) {
			mForegroundDrawable.setState(getDrawableState());
		}

		// Trigger a redraw.
		invalidate();
	}

	/**
	 * Metodo che gestisce l'operazione di disegno del drawable.
	 * */
	@Override
	protected void onDraw(Canvas canvas) {
		// First draw the image.
		super.onDraw(canvas);

		// Then draw the highlight on top of it. If the button is neither
		// focused
		// nor pressed, the drawable will be transparent, so just the image
		// will be drawn.
		mForegroundDrawable.setBounds(mCachedBounds);
		mForegroundDrawable.draw(canvas);
	}

	/**
	 * Metodo richiamato quando cambiano le dimensioni del drawable.
	 * */
	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);

		// Cache the view bounds.
		mCachedBounds.set(0, 0, w, h);
	}
}
